KANDAHAR, Afghanistan — After the Chinese Consulate in a major Pakistani city was attacked by a squad of suicide bombers last month, Pakistani officials pointed fingers at the commander of a separatist group waging an insurgency in the southwestern province of Baluchistan.

On Tuesday, a suicide bomber killed that commander, Aslam Baluch, along with five associates in an upscale neighborhood of Kandahar, in southern Afghanistan.

TAJIK.

TURKMEN.

AFGHANISTAN

Kandahar

PAKISTAN

Bolan

region

Baluchistan

IRAN

INDIA

Arabian Sea

200 MILES

By The New York Times

No group claimed responsibility for the latest Kandahar bombing. But it is widely believed to be an act of revenge for November’s consulate assault, highlighting the cross-border trading of insurgents and attacks by proxy that remains at the heart of relations between Pakistan and Afghanistan.

To Afghan officials, Tuesday’s attack bore the hallmarks of an operation directed by Pakistan’s military intelligence service, the I.S.I.

“The bomber was sent and guided by the I.S.I.,” Maj. Gen. Tadin Khan, the police chief of Kandahar, said on Thursday.

Though not specifically named by the authorities, the Taliban, many of whose leaders are believed to live in Pakistan, have carried out suicide bombings in southern Afghanistan in the past. Afghan and Western officials have long accused the Pakistani military, particularly its intelligence service, the I.S.I., of providing covert aid and direction to the Taliban as a way to wield influence in Afghanistan.

A spokesman for the Taliban, Zabihullah Mujahid, denied the group’s involvement, saying: “The incident in Kandahar and the killing of any Baluch has nothing to do with us.”

In October, General Khan’s brother, Gen. Abdul Raziq, the powerful police chief of Kandahar, was killed by a teenage infiltrator who authorities said had trained in Pakistan. General Raziq was a staunch critic of Pakistan for harboring Taliban leaders.

Pakistani officials, in turn, had accused General Raziq, who had a large network of informants and vast wealth, of stirring trouble in Baluchistan and assisting the Baluch separatists. Afghan officials confirmed that General Raziq had housed Baluch separatist leaders in Kandahar for years.

The Baluchistan Liberation Army, of which Mr. Baluch was a major commander, has waged armed resistance against the Pakistani state for more than a decade, protesting discriminatory treatment and demanding autonomy for the province.

The group has recently stepped up attacks against Pakistani military targets and Chinese targets. It sees China as an “oppressor” that is supporting the Pakistani government and plundering resources in Baluchistan. China is investing hundreds of millions of dollars to develop a port and an economic zone in the town of Gwadar in Baluchistan.

The rebel group has established a brigade to carry out suicide attacks, named after a Baluch militant who carried out a failed attack on a Pakistani prime minister in the 1970s. In one of its first operations, last August, Aslam Baluch sent his own son to target a bus carrying Chinese engineers.

Mr. Baluch arrived in Kandahar last week, according to some reports. He emerged from a meeting at a friend’s home in Aino Mina township on Tuesday, and as the participants walked to their cars, a suicide bomber approached and detonated his explosives.

“The explosion was powerful and close to us,” said Nida Mohammad, a shopkeeper near the house in Aino Mena. “We thought that a rocket landed from somewhere.”